RELATION OF BACTERIA TO DAIRY INDUSTRY. 85 



the method of simply allowing the cream to ripen 

 normally without such additions, it is a method 

 that is decidedly inferior to that which first 

 pasteurizes the cream and subsequently adds a 

 starter. 



There is still another method of adding bac- 

 teria to cream to insure a more advantageous 

 ripening, which is frequently used, and, being 

 simpler, is in many cases a decided advantage. 

 This method is by the use of what is called a 

 natural starter. A natural starter consists simply 

 of a lot of cream which has been taken from the 

 most favourable source possible that is, from 

 the cleanest and best dairy, or from the herd 

 producing the best quality of cream and allow- 

 ing this cream to stand in a warm place for a 

 couple of days until it becomes sour. The cream 

 will by that time be filled with large numbers of 

 bacteria, and this is then put as a starter into the 

 vat of cream to be ripened. Of course, in the use 

 of this method the butter maker has no control 

 over the kinds of bacteria that will grow in the 

 starter, but it is found, practically, that if the 

 cream is taken from a good source the results 

 are extremely favourable, and there is produced 

 in this way almost always an improvement in the 

 butter. 



The use of pure cultures is still quite new, 

 particularly in this country. In the European 

 butter-making countries they have been used for 

 a longer period and have become very much bet- 

 ter known. What the future may develop along 

 this line it is difficult to say ; but it seems at 

 least probable that as the difficulties in the de- 

 tails are mastered the time will come when start- 

 ers will be used by our butter makers for their 



